Helper functions updates

 - Add user levels as constants to allow wider, normalised use
 - Rework LocaleDate() to provide additional options
WebUi updates

 - Formatting updates
 - Highlight 'Add news Item' as a button rather than a link
 - Update slideshow options to  correct display in Safari
 - Correct processing in page_manager to allow saving
 - Revise error page to correctly display in contents container
 - Relabel login 'Submit' button to 'Login'
 - Additional menu corrections
 - Provide user registration option for admin regardless of web
registration status